Shell-base for cartridges.



N0. 707,68l. A Patented Aug. 26, I902.

A. T. DUNCAN. SHELL BASE FOR CARTRIDGES.

(Application filed Apr. 26, 1901.) (No lode-I.)

UNITED STATES PATENT OFFICE.

ARTHUR THOMPSON-DUNCAN, OF-CLINTON, MISSOURI.

SHELL-BASE FOR CARTRIDGES.

SPECIFICATION forming part of Letters Patent No. 707.681, dated. August 26,1 902. Applicationtiled April 26.19011 serial mo. 7,638. .(No model.)

To all whom it may concern: Be it known that I,.ARTHUR- THOMPSON DUNCAN, a' citi z'en ot' the United States of America, residing -at'the city of Clinton, in the county of Henry and State of Missouri, have invented a new and useful shell-baseto'be used in metal shells for shotguns, rifles, and

other sporting and-military firearms for thev purpose of securing the instantaneous. ignistruction upon the-inside at thepoWder-chamberas to prevent't-he fire and percussion from the exploded primer from instantly igniting and exploding the entire charge of nitro or,

other powders with-which the shells may beloaded by reason of the-fact that the primer seat and the percussion-hole e'xtend above.-

and beyondthc base-0f the shell on the inside in a manner to direct the flame from the e2;-- ploded primer to 'the'forward portion of the" charge of powder, thus igniting and exploding a sufficient quantity of the same .to dis- I charge the shot or projectile from the gun be-.

fore the remaining portion of the powder i11 shell, and O C- is the device, having an out; side format the based (1 and the circumference 'e e corresponding to the inside form and circumference of the shell. at these same points and being of a size'to fit sufficiently tight in the shell at the circumference e 6, so as to require a reasonable amount'of force to practical, durable, efficient, and inexpensive means for confining the charge'of powder in metal shells without adding materially to the -weight of the shell in such form and position with relation to the flame from the exploded primer as to insu'rethe instantaneous ignition and complete combustion of the entire charge-.ofnitro or' other powders with which circumference e e equal to about two-thirds of the shells may be loaded;-

The form and position that the charge ofpowder will be made to occupy in the shell by the use of my invention and which is best adapted to bring about the desired results is Y the bulk ofpowder resting on the primerchamber, so that the quantity of powder c0n i-. ing directly'into contact with the flame from the exploded'primer will be no greater than will-be instantly and completely ignited and so that the ignition thus produced and started will spread by reason of the unexploded particles of powder'b eing always in advance of the flame from the exploded particles in an ever-increasing vol ume, until the whole quantity of powder is thus; ignited, making't'he combustion instantaneous and complete, I

attain this object by means of the device hereinbefore named, which is. a'solidcom pact circular body madeof compressed paper or other suitably lightjand durable material, and in this instance it. is made of paper and may have the surface which is exposed to the pow-- vder lined with thin metal and having an outside form and circumference corresponding to the inside form and circumference of that, part of a particular size metal shell which the correspondingsizedevice willengage when seated therein ready for use.

" My invention is illustrated inthe accompanying drawings,iin whichv Figure 1 is an elevation, partly in section, of a metal shell,showing the form of the device and the position it will occupy when.

seated in the shell ready for use; Fig.- :Zis a top view, and Fig. 3 is a bottom View, of the device.

A is L lle body, and l; is the base, of the be driven down into position until 'it rests firmly against the base of the shell at (Z d, the

adhesionof the surfac'esat e'e thus produced being sulficient'to retain the device permanently in position, and havingalength at'the its diameter or su-ificient to extend a suitable distance above the base, as from d d to f f,

and having the hole g through the center,

into which the primer-seat 7t ex tend'sand. fits surface Z, extending from the top edge ofthe hole g'a slight distance above the top of the 'primer-seath in an outward and upward direction,"terminating at the top with then'arrow fiat edge or rim ff, and thus forming a tightly, and having a concave face or inner funnel-shaped depression, communicating at the bottom with the primer-chamber 7' through the percussion-hole 7c, The bore of the shell tapers and diminishes toward its breech, as shown in Fig. 1, and as the base .e is forced in the shell the base becomes compressed diametrically and tightly fitted frictionally therein, but yet so that the base lnay be extracted when the same becomesburned and worn after repeated use aud'another placed in the breech of the shell in lieu thereof.

I am aware that prior to my invention paper shells have been made with variousshaped bases for the purpose of facilitating l the combustion of the charge of powder.

. Therefore I do not claim as my invention any able base for acartridge-shell, said base being made of paper or other light material, of cycavity, said bore being adapted to receive the primer-chamber'in the'base of the cartridgeshell, the surface of the base which is exposed-to the powder being lined with thin metal, substantially as described.

' In'testimony that the above and foregoing is my own I hereto affix my signature in the presence of two witnesses. ARTHUR THOMPSON DUNCAN.

' VVitnessesfl CHARLES VAN WILLIAMS, 7 MARTIN M. BENNETT. 

